1. Field of the Invention
The present invention is related to an electrical connector, especially to a straddle connector which is straddle-mounted on an edge of a printed circuit board and has a common ground member for rows of signal conductors installed inside this connector to connect with the pads disposed at either one or both sides of the printed circuit board.
2. Description of the Related Art
The trend of light, thin and small design for electronic products is prevailing today. The parts used in these products are size-reduced and always rearranged for installation. Thus, the primary circuit board of these electronic products, a main functioning part in these electronic products, gets less available space to connect to other peripheral devices like CD-ROM, hard disk, etc. Therefore, some special connections contributing to space saving, like a straddle mount connector being able to reduce the final height of the assembled primary circuit board, are broadly used. A straddle mount connector is mounted on the edge of the primary circuit board and its contacts are soldered on pads formed on one of two sides of the primary circuit board. Chen et al. U.S. Pat. No. 5,292,265 and Long U.S. Pat. No. 5,893,764 both introduce connectors having two rows of contacts where contacts of one row are engaged on one side of the printed circuit board while contacts of the other row are engaged on the opposite side. A curved tail of every contact is disposed for engaging with the corresponding pad mounted on the printed circuit board due to the difference between the thickness of the printed circuit board and the distance of the two contact rows.
Tor et al. U.S. Pat. Nos. 5,823,799 and 5,971,775 show all the contacts are soldered onto only one side of the printed circuit board, no matter how many rows of contacts the connector has. This type of contact tail arrangement is more easily made and protected because it avoids potential collision in the mounting process. But the space on the edge side of printed circuit board is still limited, which results in the corresponding soldering pads on the printed circuit board being so close to each other that the soldering process is complicated.
However, high density connectors with multi rows of contacts have been introduced to meet the need of high speed transmission recently. Schmidgall et al. European Patent Application No. 01 126552 shows a connector with three rows of contacts which is straddle mounted on a printed circuit board by soldering two rows of contacts on the same side of the printed circuit board and one row of contacts on the other side. The row of contacts that is farther from the edge surface of the printed circuit board than others needs longer and specially bent tails to be engaged with the printed circuit board.
Additionally, crosstalk is usually a concern in high density connectors, especially for high speed transmission. Ground means is then added to surround contacts and shield them from each other for higher electrical performance. Cohen et al. U.S. Pat. No. 6,152,742and Grabbe et al. U.S. Pat. Nos. 5,320,541 and 5,813,871 all introduce a straddle mount connector having a ground plate disposed between two rows of contacts. The ground plate has tails extending near the tails of the contacts and are soldered onto the same edge of the printed circuit board to establish electrically grounded paths. Obviously, there are more tails, including signal and ground ones, than previously needed to connect with the printed circuit board. Therefore, to solve this space problem in Grabbe design, specialized holes on the edge of the printed circuit board are added which need additional work on the circuit board and cost expensive. This also adds extra insertion force when the connector is mounted onto the circuit board.
In high speed transmission, more than one means of ground in a parallel arrangement are possibly adopted in a high density connector design. It will become an important issue to solve the connection of the ground means to the printed circuit board where the connector is installed.
Therefore, an object of the present invention is to provide a straddle mount connector having a common ground member installed near signal conductors in the connector for ground reference, and the common ground member of the connector becomes a main connecting part of a integral conductor subassembly so that all the conductors of the connector, including signal conductors and the ground member, can be installed into the connector housing at one time for process simplification and time savings.
Another object of the present invention is to provide a straddle mount connector having a joined ground member with at least two main portions installed near different signal conductors, so that the ground path can still be established for every main portion of the ground member using fewer tails in common to electrically connect to the printed circuit board where the connector is seated, leaving the mounting space on the printed circuit board for other necessary components.
Another object of the present invention is to provide a straddle mount connector having a common ground member for at least two different rows of signal conductors and the ground member of the connector provides mounting tails sheared therefrom to be alternately mounted on two sides of the mounting edge of the printed circuit board where the connector is seated, so that the shearing location of the mounting tails can easily vary to meet the different thickness of the circuit board and the force provided by the mounting tails is large enough to help the connector remain fixedly mounted on the edge of the printed circuit board.
To obtain the above objects, an electrical connector straddle-mounted on an edge of a printed circuit board includes an insulative housing having an elongated groove for mating. A plurality of receiving channels formed adjacently to and communicated with the mating groove are arranged in two rows so that a support subassembly can be inserted and expose its portions in the mating groove. The support subassembly includes two bases each having a plurality of parallel-arranged passageways formed on one surface and protrusions formed on the other. Pin-like signal conductors are inserted into the passageways respectively along the surface of the base and a U-shaped ground member is installed abutting against the other surfaces of two bases of the support subassembly. Each signal conductor includes an engaging end exposed to the mating groove once the signal conductor is inserted into the housing accompanying the support subassembly, and a tail end extending out of the receiving channel in a suspended status. The ground member includes a plurality of contacting legs sheared from the ground member and extending for a predetermined distance to be suspended similar to the tail end of the signal conductors.
Specifically, two parallel-arranged side portions of the U-shaped ground member are integrally connected via the central portion of the ground member, and each of them is installed with one base having signal conductors disposed thereon so that the side portion can be used as ground reference for the signal conductors to reduce unnecessary noise. The support subassembly, united by the ground member, then can be installed into the connector housing at one time to save assembly process and work time. Additionally, the electrically connected side portions of the ground member can share ground paths so that the engaging tails extending from the ground member to the printed circuit board can be reduced to save the occupied space of the connector on the printed circuit board.
Furthermore, the contacting legs of the ground member are sheared from the central portion of the ground member in a row of inversely and alternately arrangement, so that they can extend out of the ground member when two side portions are bent vertically to shape the ground member. The contacting legs are alternately mounted on two sides of the mounting edge of the printed circuit board where the connector is seated to provide the larger holding force for the connector on the printed circuit board before further soldering proceeds. The shearing location of the contacting legs can easily vary to meet the different thickness of the circuit board without newly added material.
Other objects, advantages and novel features of the invention will become more apparent from the following detailed description of the present embodiment when taken in conjunction with the accompanying drawings.